NOTES ON THE MOUNT LYELL DISTKICT, 

 TASMANIA. 



By Frederick Danvers Power, F.G.S. 



In reply to my critics, I must say that I was rather sur- 

 prised to find myself credited with being the author of new 

 theories. It is possible that I am the first to apply the 

 views expressed in my paper to Tasmanian geology, but I do 

 not pretend to be the originator of what Mr. Stephens terms 

 the " water pressure and wave theory," or of the anti-true- 

 fissure-lode theory, although I am prepared to uphold them 

 until disproved, or more suitable substitutes are brought for- 

 ward. In writing my paper I took for granted that the 

 researches of such men as Dr. W. B. Carpenter, F.R.S., and 

 S. F. Emmons were known, and therefore considered it 

 unnecessary to back up my opinions by quoting them and 

 others, in the same way that it would be superfluous to quote 

 Sir Isaac Newton when mentioning gravity. 



My paper was intended to give but a sketch of the geology 

 of the Mount Lyell district. To go into detail in the present 

 state of the country would take months of residence on the 

 spot. In making my views public I was aware 

 from Tasmanian literature, as also by personal conver- 

 sation, that they were in opposition to those gener- 

 ally accepted in the island, but by bringing the results 

 of modern research to bear on local conditions, I 

 had hoped to direct thought out of the groove 

 into which it had fallen. Of course I did not expect 

 to win those who had strong views on the sub- 

 ject over to my side at once, but I did expect them 

 either to give valid arguments for their side of the question, or 

 prove mine incorrect, especially when these sentiments are due 

 to misconceptions on their part. Mr. E. M. Johnston, though 

 expressing his strong opinion against my views, does not offer 

 a single argument in favour of his, or against mine, unless 

 his statement that most geologistshave adopted the contraction 

 theory to account for mountain formations can be considered 

 one. "in replying I am debarred from elaborating on my 

 subject, as to give it full justice would require more time 

 than can at present be spared. I must, therefore, be content 

 with briefly vindicating my views. The two points on which 

 we differ are : — 



1. The main cause of mountain ranges. 



2. The nature of most so-called true-fissure-lodes. 



